(19)

(11)

EP 1 015 904 A1

(12)

(43) Date of publication: 05.07.2000 Bulletin 2000/27 (21) Application number: 97919159.0 (22) Date of filing: 18.09.1997

(51) International Patent Classification (IPC)7: G01R 33/36 (86) International application number: PCT/GB9702/524 (87) International publication number: WO 9914/615 (25.03.1999 Gazette 1999/12)

(84) Designated Contracting States: GB (71) Applicant: OXFORD ANALYTICAL INSTRUMENTS LIMITED Witney,Oxon. OX8 1TL (GB)	(72) Inventor: BLANZ, Martin Near Abingdon,Oxon OX14 4NB (GB) (74) Representative: Skone James, Robert Edmund  GILL JENNINGS & EVERYBroadgate House7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)